The invention relates to novel p-diaminobenzene derivatives and to colorants for dyeing keratin fibers and containing these compounds.
In the area of keratin fiber dyeing, particularly hair dyeing, oxidation dyes have attained substantial importance. In this case, the coloration is produced by reaction of certain developers with certain couplers in the presence of an appropriate oxidant. Suitable developers are, in particular, 2,5-diaminotoluene, 2,5-diaminophenylethyl alcohol, p-aminophenol, 4-amino-3-methylphenol and 1,4-diaminobenzene, and suitable couplers are, for example, resorcinol, 4-chlororesorcinol, 1-naphthol, 3-aminophenol, 5-amino-2-methylphenol and derivatives of m-phenylenediamine. Moreover, Unexamined German Patent Application [DE-OS] 198 22 041 describes colorants containing as developers p-phenylenediamines substituted in the 2-position.
The oxidation dyes used for dyeing human hair must meet numerous requirements in addition to that of being able to produce colorations of the desired intensity. For example, these dyes must be harmless from a toxicological and dermatological standpoint, and the hair colorations must have good light fastness, resistance to permanent waving, acid fastness and rubbing fastness. In any case, however, such colorations must remain stable over a period of at least 4 to 6 weeks in the absence of exposure to light, rubbing and chemical agents. Moreover, by combination of appropriate developers and couplers, it must be possible to create a wide range of color shades.
Currently used colorants, however, do not meet all aspects of the aforesaid requirements.
Hence, there continues to exist a need for novel developers capable of meeting the aforesaid requirements to a very high degree.
Surprisingly, in this regard, we have now found that p-diaminobenzene derivative of general formula (I) meet the requirements placed on developers to a particularly high degree. For example, the use of these developers in combination with known couplers produces intense color shades that are unusually light-fast and wash-fast.
The object of the present invention are therefore p-diaminobenzene derivatives of general formula (I) or physiologically tolerated, water-soluble salts thereof 
wherein R1, R2, R3, R4, R5, R6 and R7
independently of each other denote hydrogen, a C1-C6-alkyl group, a C1-C4-hydroxyalkyl group, a C2-C4-dihydroxyalkyl group or a C1-C4-alkoxy-(C1-C4)-alkyl group, or R1 and R2 or R3 and R4 or R5 and R6 form a four-membered to eight-membered aliphatic ring, and at least two of the R1 to R7 groups denote hydrogen;
R8 stands for hydrogen or a C1-C4-alkyl group; and
R9, R10 independently of each other denote hydrogen, a hydroxyl group, a halogen atom, a C1-C4-alkyl group, a C1-C4-hydroxyalkyl group, a C1-C4-aminoalkyl, group, an amino group, a C1-C2-alkylamino group or a C1-C4-alkoxy group.
Suitable compounds of formula (I) are, for example:
4-[3-(2,5-diaminophenyl)allylamino]aniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-(2-hydroxyethyl)-aniline; 4-[3-(2,5-diaminophenyl)allylamino]-5-(2-hydroxyethyl)aniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-chloroaniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-methylaniline; 4-[3-(2,5-diaminophenyl)allylamino]-3-(2-hydroxyethyl)aniline; 4-[3-(2,5-diaminophenyl)allylamino]-3-chloroaniline; 4-[3-(2,5-diaminophenyl)allylamino]-3-methylaniline; 4-{3-[2,5-diamino-3-(2-hydroxyethyl)phenyl]allylamino}-aniline; 4-[3-(2,5-diamino-3-chlorophenyl)allylamino]aniline; 4-[3-(2,5-diamino-3-methylphenyl)allyl]-amino]aniline; 4-[3-(2,5-diamino-6-methylphenyl)allylamino]aniline; 4-{3-[2,5-diamino-4-(2-hydroxyethyl)phenyl]allylamino}aniline; 4-[3-(2,5-diamino-4-chlorophenyl)allylamino]aniline; 4-[3-(2,5-diamino-4-methylphenyl)allylamino]aniline; 4-[3-(N2,N2-bis-methyl-2,5-diaminophenyl)allylamino]-2-aniline; 4-{3-[N2,N2-bis-(2-hydroxyethyl)-2,5-diaminophenyl]allylamino}-2-aniline; 4-[3-(N5,N5-bis-methyl-2,5-diaminophenyl)allylamino]-2-aniline; 4-{3-[N5,N5-bis-(2-hydroxyethyl)-2,5-diaminophenyl]-allylamino}-2-aniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-N,Nxe2x80x2-bis-methylaniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-N,Nxe2x80x2-bis-(2-hydroxyethyl)aniline or a physiologically tolerated salt thereof.
Preferred are compounds of formula (I) wherein (i) at least one of groups R8 to R10 denotes hydrogen, and/or (ii) R1 and R2 or R3 and R4 or R5 and R6 or all R1 to R4 or R1 to R7 groups denote hydrogen. Also preferred are compounds of formula (I) wherein R8 denotes hydrogen and R5 and R6 independently of each other denote hydrogen, a C1-C4-alkyl group, a C1-C4-hydroxyalkyl group or a C2-C4-dihydroxyalkyl group.
Particularly preferred p-diaminobenzene derivatives of formula (I) are 4-[3-(2,5-diaminophenyl)-allylamino]aniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-(2-hydroxyethyl)aniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-methylaniline; 4-[3-(2,5-diaminophenyl)allylamino]-3-methylaniline; 4-[3-(2,5-diaminophenyl)allylamino]-3-(2-hydroxyethyl)aniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-N,Nxe2x80x2-bis-methylaniline; 4-[3-(2,5-diaminophenyl)allylamino]-2-N,Nxe2x80x2-bis-(2-hydroxyethyl)aniline or physiologically tolerated salts thereof.
The compounds of formula (I) can be used either as free bases or in the form of their physiologically tolerated salts of inorganic or organic acids, for example hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, propionic acid, lactic acid or citric acid.
The p-diaminobenzene derivatives of formula (I) can be prepared by known methods of synthesis. For example, the synthesis of the compounds of the invention can be carried out as follows:
By reductive amination of a substituted benzene of formula (II) 
wherein Ra denotes a suitable protective group described, for example, in Organic Synthesis, Chapter 7 xe2x80x9cProtection for the Amino Groupxe2x80x9d, page 309 ff., Wiley Interscience, 1991; Rb has the meaning of NR1Ra or NR1R2, with an amine of formula (III) 
wherein Rc has the meaning of Ra or R6, R5, R6, R7, R8, R9 and R10 having the same meaning as in formula (I), followed by elimination of the protective group.
The p-diaminobenzene derivatives of formula (I) of the invention are readily water-soluble and give colorations of high color intensity and excellent color fastness, particularly in terms of light fastness, wash fastness and rubbing fastness. The compounds of formula (I) also have excellent storage stability, particularly as constituents of the colorants described in the following.
Hence, another object of the present invention are compositions for oxidative dyeing of keratin fibers, for example hair, furs, feathers or wool, particularly human hair, based on a developer-coupler combination, said compositions containing as the developer at least one p-diaminobenzene derivative of formula (I).
The p-diaminobenzene derivatives of formula (I) are contained in the colorants of the invention in a total amount of about 0.005 to 20 wt. %, an amount from about 0.01 to 5.0 wt. % and particularly from 0.1 to 5 wt. % being preferred.
Preferred couplers are 2,6-diaminopyridine, 2-amino-4-[(2-hydroxyethyl)amino]anisole, 2,4-diamino-1-fluoro-5-methylbenzene, 2,4-diamino-1-methoxy-5-methylbenzene, 2,4-diamino-1-ethoxy-5-methyl-benzene, 2,4-diamino-1-(2-hydroxyethoxy)-5-methylbenzene, 2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxybenzene, 2,3-diamino-6-methoxypyridine, 3-amino-6-methoxy-2-(methylamino)pyridine, 2,6-diamino-3,5-dimethoxypyridine, 3,5-diamino-2,6-dimethoxypyridine, 1,3-diaminobenzene, 2,4-diamino-1-(2-hydroxyethoxy)benzene, 2,4-diamino-1,5-di-(2-hydroxyethoxy)benzene, 1-(2-aminoethoxy)-2,4-diaminobenzene, 2-amino-1-(2-hydroxyethoxy)-4-methylaminobenzene, 2,4-diaminophenoxyacetic acid, 3-[di-(2-hydroxyethyl)amino]aniline, 4-amino-2-di-[(2-hydroxyethyl)amino]-1-ethoxybenzene, 5-methyl-2-(1-methylethyl)phenol, 3-[(2-hydroxyethyl)amino]aniline, 3-[(2-aminoethyl)amino]aniline, 1,3-di-(2,4-diaminophenoxy)propane, di-(2,4-diaminophenoxy)methane, 1,3-diamino-2,4-dimethoxybenzene, 2,6-bis-(2-hydroxyethyl)aminotoluene, 4-hydroxyindole, 3-dimethylaminophenol, 3-diethylaminophenol, 5-amino-2-methylphenol, 5-amino-4-fluoro-2-methylphenol, 5-amino-4-methoxy-2-methylphenol, 5-amino-4-ethoxy-2-methylphenol, 3-amino-2,4-dichlorophenol, 5-amino-2,4-dichlorophenol, 3-amino-2-methylphenol, 3-amino-2-chloro-6-methylphenol, 3-aminophenol, 2-[(3-hydroxyphenyl)amino]acetamide, 5-[(2-hydroxyethyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]phenol, 3[(2-methoxyethyl)amino]phenol, 5-amino-2-ethylphenol, 2-(4-amino-2-hydroxyphenoxy)ethanol, 5-[(3-hydroxypropyl)amino]-2-methylphenol, 3-[(2,3-dihydroxypropyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]-2-methylphenol, 2-amino-3-hydroxypyridine, 5-amino-4-chloro-2-methylphenol, 1-naphthol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-methyl-1-naphthol acetate, 1,3-dihydroxybenzene, 1-chloro-2,4-dihydroxybenzene, 2-chloro-1,3-dihydroxybenzene, 1,2-dichloro-3,5-dihydroxy-4-methylbenzene, 1,5-dichloro-2,4-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 3,4-methylenedioxyphenol, 3,4-methylenedioxyaniline, 5-[(2-hydroxyethyl)amino]-1,3-benzodioxol, 6-bromo-1-hydroxy-3,4-methylenedioxybenzene, 3,4-diaminobenzoic acid, 3,4-dihydro-6-hydroxy-1,4(2H)-benzoxazine, 6-amino-3,4-dihydro-1,4(2H)benzoxazine, 3-methyl-1-phenyl-5-pyrazolone, 5,6-dihydroxyindole, 5,6-dihydroxyindoline, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole and 2,3-indolinedione.
Although the advantageous properties of the p-diaminobenzene derivatives of formula (I) described here suggest that said derivatives should be used as the only developers, it is, of course, also possible to use the p-diaminobenzene derivatives of formula (I) together with known developers such as, for example, 1,4-diaminobenzene, 2,5-diaminotoluene, 2,5-diaminophenylethyl alcohol, 4-aminophenol and the derivatives thereof, for example 4-amino-3-methylphenol, 4,5-diaminopyrazole derivatives, for example 4,5-diamino-1-(2-hydroxyethyl)pyrazole, or tetraaminopyrimidines.
The couplers and developers can be contained in the colorants of the invention either alone or in admixture with each other, the total amount of couplers and developers in the colorants of the invention (based on the total amount of colorant) being in all cases from 0.005 to 20 wt. %, preferably from about 0.01 to 5.0 wt. % and particularly from 0.1 to 2.5 wt. %.
The total amount of developer-coupler combination contained in the colorants described here is preferably from about 0.01 to 20 wt. %, an amount from about 0.02 to 10 wt. % and particularly from 0.2 to 6.0 wt. % being particularly preferred. In general, the developers and couplers are used in approximately equimolar amounts. It is not disadvantageous in this respect, however, if the developers are present in a certain excess or deficiency (for example, in a coupler-to-developer ratio of 1:2 to 1:0.5).
Moreover, the colorants of the invention can additionally contain other dye components, for example 6-amino-2-methylphenol and 2-amino-5-methylphenol, as well as other common direct dyes, for example triphenylmethane dyes such as 4-[(4xe2x80x2-aminophenyl)-(4xe2x80x2-imino-2xe2x80x3,5xe2x80x3-cyclohexadien-1xe2x80x3-ylidene)methyl]-2-methylaminobenzene monohydrochloride (C.I.1 42 510) and 4-[(4xe2x80x2-amino-3xe2x80x2-methylphenyl)-(4xe2x80x3-imino-3xe2x80x3-methyl-2xe2x80x3,5xe2x80x3-cyclohexadien-1xe2x80x3-ylidene)methyl]-2-methylaminobenzene monohydrochloride (C.I. 42 520), aromatic nitro dyes such as 4-(2xe2x80x2-hydroxyethyl)aminonitrotoluene, 2-amino-4,6-dinitrophenol, 2-amino-5-(2xe2x80x2-hydroxyethyl)aminonitrobenzene, 2-chloro-6-(ethylamino)-4-nitrophenol, 4-chloro-N-(2-hydroxyethyl)-2-nitroaniline, 5-chloro-2-hydroxy-4-nitroaniline, 2-amino-4-chloro-6-nitrophenol and 1-[(2xe2x80x2-ureidoethyl)amino]-4-nitrobenzene, azo dyes such as sodium 6-[(4xe2x80x2-aminophenyl)azo]-5-hydroxynaphthalene-1-sulfonate (C.I. 14 805) and disperse dyes, for example 1,4-diaminoanthraquinone and 1,4,5,8-tetraaminoanthraquinone.
1 C.I.=Color Index-Translator 
The colorants of the invention can contain these dye components in an amount from about 0.1 to 4.0 wt. %.
Naturally, the couplers and developers and the other dye components, as long as they are bases, can also be used in the form of physiologically tolerated salts of organic or inorganic acids, for example hydrochloric acid or sulfuric acid orxe2x80x94providing that they contain aromatic OH groupsxe2x80x94in the form of salts of bases, for example as alkali metal phenoxides.
Moreover, if the colorants are to be used for coloring hair, they can contain other common cosmetic additives, for example antioxidants such as ascorbic acid, thioglycolic acid or sodium sulfite, as well as perfume oils, complexing agents, wetting agents, emulsifiers, thickeners and hair-care agents. The colorant of the invention can be formulated as a solution, particularly as an aqueous or aqueous-alcoholic solution. A particularly preferred formulation form, however, is a cream, gel or emulsion. Such a composition consists of a mixture of the dye components and the usual additives employed for such compositions.
Common additives to solutions, creams, emulsions or gels are, for example solvents such as water, lower aliphatic alcohols, for example ethanol, propanol or isopropanol, glycerol or glycols such as 1,2-propylene glycol, moreover wetting agents or emulsifiers from the classes of anionic, cationic, amphoteric or nonionic surface-active agents, for example fatty alcohol sulfates, ethoxylated fatty alcohol sulfates, alkylsulfonates, alkylbenzenesulfonates, alkyltrimethylammonium salts, alkylbetaines, ethoxylated fatty alcohols, ethoxylated nonylphenols, fatty acid alkanolamides and ethoxylated fatty esters, furthermore thickeners such as the higher fatty alcohols, starch, cellulose derivatives, petrolatum, paraffin oil and fatty acids, also hair-care agents such as cationic resins, lanolin derivatives, cholesterol, pantothenic acid and betaine. The cited constituents are used in amounts commonly employed for such purposes, for example the wetting agents and emulsifiers at a concentration of about 0.5 to 30 wt. %, the thickeners in an amount from about 0.1 to 25 wt. % and the hair-care agents at a concentration from about 0.1 to 5.0 wt. %.
Depending on the composition, the colorants of the invention can be weakly acidic, neutral or alkaline. Preferably, the colorants of the invention have a pH of 5 to 11.5, a pH of about 6.5 to 10.5 being particularly preferred. Adjustment to a basic pH is preferably done with ammonia, but it can also be done with an organic amine, for example monoethanolamine and triethanolamine, or even with an inorganic base such as sodium hydroxide or potassium hydroxide. Suitable for adjustment to an acidic pH are inorganic or organic acids, for example phosphoric acid, acetic acid, citric acid or tartaric acid.
For oxidative dyeing of hair, the afore-described colorants are mixed with an oxidant just before use, and the resulting mixture is applied to hair in an amount sufficient for the hair-dyeing treatment, in general about 60 to 200 grams, depending on the hair fullness.
Suitable oxidants for developing the hair coloration are mainly hydrogen peroxide or its products of addition to urea, melamine, sodium borate or sodium carbonate, in the form of a 3-12%, preferably 6% aqueous solution, atmospheric oxygen also being suitable. When a 6% hydrogen peroxide solution is used as oxidant, the weight ratio of hair colorant to oxidant is from 5:1 to 1:2, but preferably 1:1. Larger amounts of oxidant are used primarily at higher dye concentrations in the hair colorant or when strong bleaching of the hair is wanted at the same time. The mixture is allowed to act on the hair at 15 to 50xc2x0 C. for about 10 to 45 min, preferably 30 min, after which the hair is rinsed with water and dried. Optionally, following this rinsing, the hair is washed with a shampoo and optionally post-rinsed with a weak organic acid, for example citric acid or tartaric acid. The hair is then dried.
The colorants of the invention containing a p-diaminobenzene derivative of formula (I) as developer give hair colorations of excellent color fastness, particularly in terms of light fastness, wash fastness and rubbing fastness. As far as the dyeing properties are concerned, the hair colorants of the invention provide a wide range of different color shades from blond to brown, purple, violet and even blue and black, depending on the type and composition of the dye components. Such color shades are characterized by unusual color intensity. The very good coloring properties of the hair colorant of the present invention also manifest themselves in that these colorants make it possible to dye graying hair, chemically not previously damaged, without any problems and with good covering power.
The following examples will explain the object of the invention without limiting its scope.